Jets and Dijets in Au+Au and p+p Collisions at RHIC

Recent data from RHIC suggest novel nuclear effects in the production of high $p_T$ hadrons. We present results from the STAR detector on high $p_T$ angular correlations in Au+Au and p+p collisions at $\sqrt{s}=200$ GeV/c. These two-particle angular correlation measurements verify the presence of a partonic hard scattering and fragmentation component at high $p_T$ in both central and peripheral Au+Au collisions. When triggering on a leading hadron with $p_T>$4 GeV, we observe a quantitative agreement between the jet cone properties in p+p and all centralities of Au+Au collisions. This quantitative agreement indicates that nearly all hadrons with $p_T>$4 GeV/c come from jet fragmentation and that jet fragmentation properties are not substantially modified in Au+Au collisions. STAR has also measured the strength of back-to-back high $p_T$ charged hadron correlations, and observes a small suppression of the back-to-back correlation strength in peripheral collisions, and a nearly complete disappearance of back-to-back correlations in central Au+Au events. These phenomena, toghether with the observed strong suppression of inclusive yields and large value of elliptic flow at high $p_T$, are consistent with a model where high $p_T$ hadrons come from partons created near the surface of the collision region, and where partons that originate or propagate towards the center of the collision region are substantially slowed or completely absorbed.Comment: Proceedings of Quark Matter 2002, to appear in Nucl. Phys.

Eye-Safe Solid-State Quasi-CW Raman Laser with Millisecond Pulse Duration

We demonstrate the first quasi-CW (ms-long pulses, pump duty cycle of 10%) end-diode pumped solid state laser generating eye-safe radiation via intracavity Raman conversion. The output power at the first Stokes wavelength (1524 nm) was 250 mW. A theoretical model was applied to analyze the laser system and provide routes for optimization. The possibility of true CW operation was discussed.Comment: Preprint accepted for publication in Optics Communications on Feb 6, 201

Jet properties from di-hadron correlations in p+p collisions at s**(1/2) = 200-GeV

An analysis of high pT hadron spectra associated with high pT $\pi^0$ particles in p+p collisions at s**(1/2) = 200-GeV is presented. The shape of the azimuthal angular correlation is used to determine the value of partonic intrinsic momentum \sqrt{\left} = 2.68 \pm 0.07(\rm stat) \pm 0.34(\rm sys) GeV/c. The effect of kT-smearing of inclusive $\pi^0$ cross section is discussed.Comment: To appear in the proceedings of 2nd International Conference on Hard and Electromagnetic Probes of High-Energy Nuclear Collisions (Hard Probes 2006), Asilomar, Pacific Grove, California, 9-16 Jun 200

Results and Perspectives in HEP, vis-a-vis Lattice QCD

I review in this presentation some aspects of phenomenology in High Energy Physics which are related to recent and possibly future progress in lattice QCD. In particular, I cover (i) the extraction of CKM matrix elements from B physics, (ii) the determination of epsilon'/epsilon, as well as (iii) some issues emerged in the physics of high energy jets produced in hadronic collisions, where input from non-perturbative calculations would benefit our capability to perform better theoretical predictions.Comment: 13 pages, Latex, 9 figures. Plenary talk delivered at the XVIIth International Symposium on Lattice Field Theory, Pisa, Ital

Driving-dependent damping of Rabi oscillations in two-level semiconductor systems

We propose a mechanism to explain the nature of the damping of Rabi oscillations with increasing driving-pulse area in localized semiconductor systems, and have suggested a general approach which describes a coherently driven two-level system interacting with a dephasing reservoir. Present calculations show that the non-Markovian character of the reservoir leads to the dependence of the dephasing rate on the driving-field intensity, as observed experimentally. Moreover, we have shown that the damping of Rabi oscillations might occur as a result of different dephasing mechanisms for both stationary and non-stationary effects due to coupling to the environment. Present calculated results are found in quite good agreement with available experimental measurements

Spatial Solitons in Media with Delayed-Response Optical Nonlinearities

Near-soliton scanning light-beam propagation in media with both delayed-response Kerr-type and thermal nonlinearities is analyzed. The delayed-response part of the Kerr nonlinearity is shown to be competitive as compared to the thermal nonlinearity, and relevant contributions to a distortion of the soliton form and phase can be mutually compensated. This quasi-soliton beam propagation regime keeps properties of the incli- ned self-trapped channel.Comment: 7 pages, to be published in Europhys. Let